1. Field of the Invention
The present invention relates to a magnetic recording medium which has a magnetic layer containing nanoparticles.
2. Description of the Related Art
It is important to reduce the size of magnetic particles contained in a magnetic layer to enhance magnetic recording density. In magnetic recording media which are widely used as video tapes, computer tapes, disks, and the like, when ferromagnetic bodies thereof have the same mass, noise becomes smaller as particle size decreases.
Promising magnetic particle materials for the enhancement of magnetic recording density include CuAu type or Cu3Au type ferromagnetic ordered alloys. It is known that ferromagnetic ordered alloys have large crystal magnetic anisotropy due to the distortion that occurs at the time of ordering and show ferromagnetism even when the magnetic particle size is reduced (see, for example, Japanese Patent Application Laid-open (JP-A) No. 2002-157727 and the pamphlet of International Publication No. 98/22942).
On the other hand, reducing the magnetic particle size and increasing the recording density of a magnetic recording medium means reducing a minimum recording volume, thereby making the recording medium more susceptible to being affected by dust. A magnetic recording medium has actually been made by applying a FePt nanomagnetic body of the CuAu type onto a Si substrate and annealing the same. As a result, it was discovered that the medium is susceptible to dust adhesion. This is a problem that must be solved in order to put such technology to practical use.